Composition and process for crease-and wrinkleproofing cellulosic textile material



United States Patent COMPOSITION AND PROCESS FOR GREASE- AND WRINKLEPROOFENG CELLULOSIC TEX- TILE MATERIAL Robert L. Holbrook, Riderwood, Md., and Richard L.

Doerr, Niagara Falls, N.Y., assignors to Olin Mathieson Chemical Corporation, a corporation of Virginia No Drawing. Application April 28, 1958 Serial No. 731,147

14 Claims. (Cl. 8116.3)

This invention relates to the impregnation of cellulosic textiles in order to make them resistant to creasing and wrinkling.

It is well known that textiles are easily wrinkled in use, and that such wrinkling is undesirable. Thus, untreated wearing apparel generally requires frequent pressings in order to maintain an acceptable appearance of the garments.

:Various compounds have been impregnated into textiles in order to alleviate wrinkling and creasing, the most common ones being urea-formaldehyde resins, cyclic ethyleneurea formaldehyde resins, melamine formaldehyde resins, guanazole-formaldehyde resins and urazoleformaldehyde resins and certain ethers bearing epoxy groups on opposite ends of the molecule. Such compounds are able to impart varying degrees of creaseresistance giving rise to textiles called minimum care fabrics which require only light pressing after laundering, and to wash and wear fabrics which require little or no pressing after laundering. The degree of creaseresistance attained depends upon the type of agent applied, the amount applied, and the method of curing the anti-wrinkling agent after it is applied to the cloth.

In practice, however, the maximum crease-resistance which any agent is capable of rendering is seldom employed. Prior creaseproofers generally have an adverse elfect on the strength of textiles. As the degree of creaseproofing with any given agent is increased, there is an accompanying increase in fiber degradation resulting in greater tearability and tensile strength loss, less desirable hand or general feel of the textile, and an increase in chlorine retention upon bleaching which results in discoloration and a further weakening of the textile fibers. Thus, the creaseproofing which has been done with such agents as mentioned above has been a compromise between maximum creaseproofing and minimum fiber degradation. No prior creaseproofing agents have been excellent in both characteristics as'well as economical.

In co-pending application Serial No. 731,146, filed of even date herewith, a series of compositions based on hydrazides of alkylene d-ibasic acids are described. Those compositions are superior creaseproofing agents over any described in the prior art, in that they exhibit negligible chlorine retention, and thus negligible fiber degradation due to chlorine retention, at use levels sufiicient to impart a high degree of wrinkle resistance to cellulosic textiles. The creaseproofers described in this invention are generally superior to any described in the prior art and even possses distinct advantages over those described in the aforementioned co-pending application. These advantages, attributable to an ether or thioether linkage, are greater durability to washing and scouring, greater wrinkle resistance at an equal use level, effectiveness in creaseproofing at lower use levels, better .stability of the aqueous composition and lower cost.

Patented Sept. 15, 1953 A particularly important property of any anti-wrinkling agent is durability, i.e., the ability to stay within the textile during alkaline or acid scours and laundering. Materials presently being used commercially have deficiencies in these respects. Thus, when cotton textiles are laundered, after being treated with a typical commercial ethyleneurea-formaldehyde condensation product, they generally lose 10 to 15 of crease angle, while cotton textiles impregnated with the materials of this invention seldom lose as much as 10 of crease angle during several launderings.

There has now been discovered a class of reaction products which are superior creaseproofing agents, in that they exhibit negligible chlorine retention, and thus negligible fiber degradation due to chlorine retention, at use levels suflicient to impart a high degree of crease resistance to cellulosic textiles, such as cotton, linen and regenerated cellulose. The products produce a durable crease-proofed finish which is not readily removed by washing or laundering and which is compatible with other textile-treating agents such as softeners, water repellants, dyes, etc. In addition, the treatment of the present invention imparts mildew-resistant properties to cotton, particularly important in tarpaulins or other cotton materials which may be in contact with soil for extended periods. Furthermore, the reaction products of this invention can be readily and economically prepared from commercially available chemicals. f

The creaseproofers are reaction products of formaldehyde (including conventional sources thereof such as paraformaldehyde) and dihydrazides of the general formula R(CONHNH wherein R is a saturated chain of 2 to 6 carbon atoms and is interrupted by one or two oxygen or sulfur atoms in the form of ether or thioether linkages, for example, diglycolic acid, thiodiglycolic acid, HOOCCH OCH -CH OCH COOH and the like, or mixtures of such dihydrazides. The crease proofers can be prepared by reacting from 4 to 20 or more moles of formaldehyde (preferably from 6 to 15 moles of formaldehyde) and one mole of the dihydrazide in aqueous solution under slightly acidic to alkaline conditions at a pH of about 6-11 and preferably about 7.5 to 9.5. The reaction is carried out preferably from about 10 C. to about 50 C. although lower and higher temperatures can be used. The reaction products thus produced are soluble in water. The solution so prepared, containing preferably about 2 to 20% or more by weight of the lreactionproduct, can be applied to the cellulosic textile directly. However, a more durable finish is obtained if the reaction product of formaldehyde and d'ihydrazide is allowed to stand for up to about 24 hours. After this time the solution, whichbecomes more acid as it stands, is padded onto a cellulosic textile or made neutral or alkaline, for example with dilute caustic, and padded onto the textile.

In accordance with the invention a solution prepared as described above and containing from about 2 percent to about 20 percent or more by Weight of the reaction product of 4 to 20 or more moles of formaldehyde with one mole of the dihydrazide or mixture of dihydrazides is padded onto the cloth, in the usual manner and preferably while the padding bath has a pH from about 5 to about 7, to the extent that the dry pick-up or add-on is between about 1 percent and 25 percent by weight, based on the weight of the dry cloth. An add-on or dry pick-up of over 25 percent can be used but there is generally insuflicient added advantage to justify this. About 0.1 percent to 2.0 percent by weight of a catalyst, based on the weight of the padding bat h, ca'n be added to the padding bath to facilitate the curing step and to produce a more durable finish. Examples of suitable catalysts are magnesium chloride, aluminum chloride, aluminum formate, aluminum tartrate, p-toluene sulphonic acid, its ammonium and amine salt and other salts of amines, for example methylamine hydrochloride and piperidine hydrochloride.

, The curing step, i.e., the reaction of 'theformaldehy'dedihydrazide adduct with the' textile is'carried out bystandar d procedure. Thus, the wet textile is subjected to drying at an elevated temperature, for example 18025'0 F., and then further heated to effect the curing. Complete cure can be obtained byheatingat 300 'F. to 400 'F. for 2 to 1 minutes. The curing period is'tempera'ture dependent and can be varied over a wide range. Thus, complete curing can also be attained in 15 to 60 seconds at 500 F. After the cloth has been cured, it can be finished according to standard textile mill procedure. An alkaline scour generally follows the crease-proofing process to remove any excess, unreacted creaseproofing agent and to improve the hand, or feel, of the cloth. Normal finishing operations can include calendaring, framing, blueing, compressive shrinking, etc. a

It is believed that the creaseproofingcompositions of this invention react with the textile fibers and do not merely exist physically within the fibers. This is shown by the inertness of the creaseproofcd textiles of this invention to acid and alkaline scouring solutions. In contrast, the reaction products of dihydrazides and formaldehyde, when prepared according to this invention and cured but not applied to cellulosic textiles are generally softened, swollen or dissolved by hot water. Furthermore, it has been reported (Textile Research Journal, 26, 940-7 (1956) WE. E. Linekin et al.) that melamine-formaldehyde resinsand urea-formaldehyde resins react with cellulose and thatthis reaction product is responsible for imparting anti-wrinkling properties to-the textiles.

The reduced chlorine retention inherent in the present creaseproofing agents is essential in maintaining 'fiber strength. Other nitrogencontaining creaseproofing'agents generally retain suflicient chlorine from bleaching baths to seriously damage textile fibers, and certain of them are so objectionable in this respect that they cannot be used on textiles which are to be bleached.

The following examples further illustrate the invention and demonstrate the superiority of the formaldehydedihydrazine creaseproofing compositions. In the examples, the term mole signifies gram moles.

Example I About 1.42 moles of formaldehyde in the form'of a 37 weight percent aqueous solution were mixed with -405 milliliters of water, and 0.237 mole of 'diglycolic acid dihydra'zide was slowly added thereto with stirring, while maintaining the pH of the mixture'at 9.5 by the slow addition of dilute (10 weight percent) aqueous caustic. The resulting solution was then stirred at room temperature for 30 minutes.

3.2 grams of magnesium chloride hexahydrate were added to the above-described solution, resulting in a pH change to 8.4. The entire solution was then divided into four equal parts and two of these parts were diluted with equal parts of Water. This resulted in two solutions containing percent by weight and two solutions containing percent by weight of the dihydrazide-formaldehyde reaction product. These solutions were then padded onto Indian Head cotton and onto 80 '4l00mer ce'rized and bleached cotton sheeting. The cl'oths' were dried and cured and the'following'results were observed. The cyclic ethylene-uIea-formaldehyde adduct is included as a typical, commercially available crease'proofingageiit for comparison:

The crease angle was determined (AATCC tentative testmethod 65-53) by folding the cloth in'half under slight pressure and measuring the angle between the halves after releasing the pressure. Thus, an angle of 180 represents the maximum angle obtainable, i.e. the cloth recovered completely and is flat. The tensile strength was measured by means of a Scott Tensile Tester. In this test the cloth is subjected-to a stretchingforce, without tearing or shearing.

Example -I[ The fiber damage resulting from chlorine retention was determined for several of the creaseproofers of this invention, and for several commercial materials. The test (Tentative Test -Method AATCC 69-52) involved soaking a piece of the creaseproofed cloth in a dilute sodiumhypochlorite solution to simulate bleaching. The cloth is then dried and given a standard scorch by heating 'itbetween electrically heated metal plates, hinged and weighted so that a test specimen may bepressedat a definite temperature under a definite pressure. The cloth is then given a tensile strength test and the loss in tensile srength is recorded in percent. Thus, if the force required totear the treated cloth is three-fourths of that required to tear the creaseproofed but unbleached cloth, the tensile strength loss is said to be 25 percent.

When the above-described test was performed on a typical commercial cyclic ethyleneurea-formaldehyde creaseproofing agent, using Indian Head cotton, the tensile strength loss was found to be 75 percent and the originally white cloth was discolored to a greenish yellow. Prior nitrogen-containing creaseproofers generally retain chlorine from bleaching 'baths tothe extent that fiber damage is from about 50 to percent. The creaseproofers of this invention generally retain-insufficient chlorine to cause a 10 percent loss in fiber strength. When a cutting of Indian Head cotton was tested by .the above procedure, after being padded with the 'diglycolic dihydrazide-formaldehyde formulation (molar ratio 1:6) to the extent of 5 percent add-on, it was found that the tensile strength loss was only 4 percent and that no color developed in the cloth.

Example III Eighteen grams of the dihydrazide of 3-(2-ca'rboxyethoxy) propionic (H N OCCH CH OCH CH CON H acid was slowly added to 49 grams of 37 weight percent aqueous formaldehyde with stirring at room temperature. The pH of the mixture was maintained about9l0 to 9.5 by the incremental additionof dilute caustic. To the above solution there was added about 400 grams of water, 3.6 grams of magnesium chloride and sufficient hydrochloric acid to lower the pH to 4.5. After 5 hours the pH was raised to 7.0 by means of dilute caustic and the solution was padded on Indian Head cotton, having a crease angle of 76, by means of a standard textile padder with the rollpressure adjusted to give 75 percent wet pick-up. The cloth was then dried on a dry-can and cured for4 minutes'at 350 F. The crease angle'was foun'dto be 122, the tear strength loss 37'perce'nt, and the tensile strength loss only 16' percent.

asotsse 5 Example IV Grams Grams Adipic Dihydrazide Diglycolic Dihydrazide. 32.4 35% Aq. formaldehyde. 120 35% Aq. formaldehyde" 97 Water 961 Water 726 In both instances the dihydrazide was slowly added to the aqueous formaldehyde dissolved in the amounts of water listed, with stirring, at room temperature, while the pH of'the solution was maintained at 9.0 to 9.5 by incremental addition of dilute aqueous caustic. After the reaction was complete, as denoted by a clear solution, magnesium chloride was added to both solutions to the extent of percent by weight, based on the weight of the dihydrazide-formaldehyde adduct. The pH of both solutions was lowered to 4.0 to 4.5, by the addition of hydrochloric acid, and maintained there for 10 seconds in the case of (A), and 5 hours in the case of (B), after which times the pH in both cases, was increased to 7.0 to 7.5 by addition of aqueous caustic.

Indian Head cotton, having an initial crease angle of about 70 was padded with these solutions. The wet pick-up was about 116 percent and the dry pick-up about 5.2 percent in both cases. After drying on a dry-can, the cloth was cured in a curing oven for 4 minutes at 400 F. The crease angle of the cloth treated with the adipic dihydrazide product exhibited a crease angle of 118 before alkaline scouring and 935 after alkaline scouring, while that treated with the diglycolic dihydrazide formulation exhibited a crease angle of 127 before alkaline scouring and 123 after alkaline scouring.

These results indicate the typically superior creaseproofing properties and durability of formulations based on the dihydrazides of the ether or thioether acids described in this invention.

Example V About 18 grams of paraformaldehyde was suspended in 400 milliliters of distilled water. The mixture was heated to 90 C. and maintained at a pH of 9.3 while 16 grams of diglycolic dihydrazide was added thereto with stirring until a homogeneous solution was obtained. This solution was padded onto Indian Head cotton, without a catalyst at room temperature, to the extent that the dry pick-up was only 2.9 percent. The cloth was dried and then cured at 340 F. for four minutes. At this low use level the crease angle of the treated cloth was 110.

Example VI About 18 grams of paraformaldehyde was suspended in distilled water at room temperature. The mixture was stirred and maintained at a pH of 9.2 with dilute caustic while 24 grams of diglycolic dihydrazide was added thereto. Hydrochloric acid was added to the solution until the pH dropped to 5.5. About 5 percent by weight of alum'inum'formate, based on the weight of the dihydra- Zide-formaldehyde reaction product, was dissolved in the solution. The solution was then padded onto Indian Head cotton having an initial crease angle of 76. The wet pick-up was 97 percent and the dry pick-up 6.3 per: cent. After the cloth was dried it was cured in a curing oven for 10 minutes at 320 F. The crease angle was then found to be 108 and the tensile strength loss 27 percent.

Example VII Thiodiglycolic dihydrazide grams) was dissolved in 369 milliliters of water at 150 F. The pH was adjusted to 8.5 and at a temperature of 120 F., 49 milliliters of 37 weight percent formaldehyde solution was added. After 45 minutes standing 7.0 grams of magneg. sium chloride (MgCl -6H O) was added, the pH was adjusted to 7.0 and the solution was padded onto 78 x 84 cotton sheeting with a wet pickup of 81.3 percent. After drying and curing for 4 minutes at 191 C., the crease angle measured 119 compared with 62 for the untreated cloth.

Example VIII Nineteen grams of oxydipropionic dihydrazide, O(CH CH CONHNH was dissolved in 392 milliliters of water with warming and 45 milliliters of 37 weight percent aqueous formaldehyde was added. The pH was adjusted to 8.5 and the solution was allowed to stand for 45 minutes. Then 37 milliliters of aqueous'magnesium chloride solution containing 10 weight percent of MgCl was added, the pH was adjusted to 7.0 and the solution was padded onto 78 x 84 cotton sheeting. Wet pickup was 77.3 percent. After drying and then curing at 191 C. for 4 minutes, the cloth showed a crease angle of 93 compared with 61 for the untreated cloth.

Example IX A solution was prepared by dissolving 0.06 gram mole of diglycolic dihydrazide and 0.04 gram mole of adipic dihydrazide in 200 grams of water. A solution of 48.7 grams of 37 weight percent aqueous formaldehyde in 200 :grams of water was adjusted to pH 7.6 by addition of one weight percent aqueous caustic soda. The mixed hydrazide solution was added to the formaldehyde solution and the composition allowed to stand for several days.

The mole ratio of hydrazides used in preparing the above solution was 2:3 of adipic to diglycolic dihydrazide. Other solutions were prepared by the identical procedure where the mole ratio was 1:4 and 0:5.

To each of the above solutions was added MgCl .6H 0 sufficient to provide 10 percent of MgCl based on the weight of the original hydrazides and formaldehyde. The

pH was adjusted to 7.0 and each solution was padded onto swatches of cotton sheeting. The cloths were dried and then cured at 191 C. for 4 minutes. The swatches were scoured by agitating in an alkaline solution of a polyoxyalkylated higher alcohol detergent and sodium perborate, rinsed and dried. The following table shows the wet pickup which varied slightly and the crease angle and tensile strength results on each group of swatches.

Example X A solution of 47.5 grams of 37 weight percent aqueous formaldehyde in 131 milliliters of water was brought to a pH of 10 by the addition of 20 weight percent aqueous caustic. To this solution was added 16.2 grams of diglycolic dihydrazide in small portions over a period of 3 minutes. The solution was acidified to pH 4.5 by the addition of 50 percent sulfuric acid and maintained there for one minute. Aqueous caustic (20 weight percent) was added to bring the'p-H to 8 and 7.3 grams of magnesium chloride was added. Linen strips were padded through the solution and then dried at 200 to 220 F. for 3 minutes. They were cured at 325 F. for 3 minutes and then re-mercerized by soaking in 60 Tw. caustic at F. for 10 minutes. After scouring with soap and soda ash solution at 180 F. they were washed with water and bleached with hydrogen peroxide. The strips were scoured with 5 percent acetic acid, rinsed and dried. The anticrease property was measured by the TBL (Tootal- Broadhurst-Lee) method described by Buck et al., Textile 7 Research Journal, 19, 234- (1949) and by Marsh, An Introduction to Textile Finishing (Wiley, 1951), pages 338-9. The values in centimeters were 3.1 and 3.2 for warp and fill respectively. Tensile strengths were 80 and 98 pounds per inch for warp and fill respectively. The hand of the treated linen was good. The preceding values compare with values in the TBL test for crease resistance and tensile strength of 1.5 cm. and 100 pounds, respectively, for the untreated linen.

Example XI A sample of 80 [plain weave rayon, having a crease angle 109 and a tensile strength of 45 pounds, was impregnated to a wet pickup of 84 percent by weight with a padding solution containing percent by weight of diglycolic dihydrazide and formaldehyde in the mole ratio of l to 12, 0.5 percent by weight of ammonium p-toluene sulfonate, 0.2 percent of a nonionic wetting agent, 2.0 percent of a commercial softener of the emulsified polyethylene type and about 88 percent by weight of water. The impregnated cloth was heated at about 200 F. until almost dry and then cured at 330 F. for four minutes. After scouring and drying the cloth had a crease angle of 130 and a tensile strength of 52 pounds.

Example XII The following solutions were made up by dissolving diglycolic hydrazide in water and slowly adding this solution to aqueous formaldehyde. The catalyst was then added, the percent shown being based on the weight of the solution. After padding these solutions on cuttings of the particular cloth shown, to the extent of the wet pick-up listed, the cloths were dried and cured at the temperature shown for the period shown. Average crease angles and tensile strengths for' the cloths appear at the bottom of each column:

Regen- Cotton Linen Linen er'ated Cellulose Water, grams 88. 7 90 84 I70. 00 CHzO, grams 7. 7 6. 3 11. 05 16. 54 Hydrazide, grams.-- 2. 3. 1 4. 95 7. 46- Mole Ratio OHgO/hydX3Zid0 18:1 9:1 12:1 12:1 MgOl percent 0. 6 0. 5 0.8 1 APTS '1. 0' Wet Pick-up, percent, 78 79 86 91 Cure Temperature, F; 3G0 350 370 330 Cure Time, minutes 4 4 2 4 Crease Angle, degrees 131 131 129 129 Tensile Strength, pounds 28 48 47 29 1 Ammonium p-tolueue sultonate.

This application is a continuation-in-part of copending application Serial No. 658,227, filed May 10, 1957, now abandoned, and is also a continuation-in-part of copending application Serial No. 669,975, filed July 5, 1957, now abandoned.

What is claimed is:

1. A method for the impregnation of a textile fabricat'ed -from a material selected from the group consisting of cellulose and regenerated cellulose to render it resistant to creasing and wrinkling which includes the steps ofimpregnating the textile with a solution of a reaction product of formaldehyde and a dihydrazide of the formula R(CONHNH obtained by reacting formaldehyde and the dihydrazide at apH of from 6 to 11 in a molar ratio of formaldehyde to the dihydrazide within the range from 4 to 20, the said reaction product being soluble in water to the extent of at least 2 percent, and heating the impregnated textile to dry it and to provide a textile resistant to creasing and wrinkling, R being an alkylene group containing from 2 to 6 carbon atoms interrupted by from 1 to 2 atoms selected from the group consisting of oxygen atoms and sulfur atoms.

2. The method of claim 1 wherein R(CONHNH is diglycolic acid dihydrazide.

3. The method of claim 1 wherein R(CONHNH is 3-(2-carboxethoxy) propionic acid dihydrazide.

4. The method of claim 1 wherein said textile is cotton.

5. The method of claim 1 wherein said aqueous solution utilized in the step of impregnating the textile contains 0.1 to 2 percent by weight of an acid-acting curing catalyst.

6. The method of claim 5 wherein said catalyst is magnesium chloride.

7. The method of claim 5 wherein said catalyst is ammoniurn p-toluene sulfonate.

8. A textile fabricated from a material selected from the group consistingof cellulose and regenerated cellulose which has been rendered resistant to creasing and wrinkling by the process of claim 1.

9. A cotton textile which has been rendered resistant to creasing and wrinkling by the process of claim 1.

10. cotton textile which has been rendered resistant to creasing and wrinkling by the process of claim 2.

11. A cotton textile which has been rendered resistant to creasing and wrinkling by the process of claim 3.

12. A composition of matter suitable for use in the impregnation of a textile fabricated from a material selected from the group consisting of cellulose and re generated cellulose to render it resistant to creasing and wrinkling consisting essentially of a solution containing at least 2 per cent by weight of a reaction product of formaldehyde and dihydrazide of the formula obtained by reacting formaldehyde and the dihydrazide at a pH of from 6 to 11 in a molar ratio of formaldehyde to the dihydrazide within the range from 4 to 20, R being an alkylene group containing from 2 to 6 carbon atoms interrupted by from 1 to 2 atoms selected from the group consisting of oxygen atoms and sulfur atoms.

13. The composition of claim 12 wherein R(CONHNH is diglycolic acid dihydrazide.

14. The composition of claim 12 wherein R(CONHNH is 3-(2-carboxyethoxy propionic acid dihydrazide.

References Cited in the file of this patent UNITED STATES PATENTS 2,161,808 Finlayso'n' et al. June 13, 1939 2,317,756 Graenacher et al Apr. 27, 1943 2,391,942 Burke Jan. 1, 1946 2,509,183 Austen May 23, 1950 2,597,467 Fisher et al May 20, 1952 2,668,154 Orth Feb. 2, 1954 2,845,400 Rudner July 29, I958 

1. A METHOD FOR THE IMPREGNATION OF A TEXTILE FABRICATED FROM A MATERIAL SELECTED FROM THE GROUP CONSISTING OF CELLULOSE AND REGENERATED CALLULOSE TO RENDER IT RESISTANT TO CREASING AND WRINKLING WHICH INCLUDES THE STEPS OF IMPREGNATING THE TEXTILE WITH A SOLUTION OF A REACTION PRODUCT OF FORMALDEHYDE AND A DIHYDRAZIDE OF THE FORMULA R(CONHNH2)2 OBTAINED BY REACTING FORMALDEHYDE AND THE DIHYDRAZIDE AT A PH OF FROM 6 TO 11 IN A MOLAR RATIO OF FORMALDEHYDE TO THE DIHYDRAZIDE WITHIN THE RANGE FROM 4 TO 20, THE SAID REACTION PRODUCT BEING SOLUBLE IN WATER TO EXTENT OF AT LEAST 2 PERCENT, AND HEATING THE IMPREGNATED TEXTILE TO DRY IT AND TO PROVIDE A TEXTILE RESISTANT TO CREASING AND WRINKLING, R BEING AN ALKYLENE GROUP CONTAINING FROM 2 TO 6 CARBON ATOMS INTERRUPTED BY FROM 1 TO 2 ATOMS SELECTED FROM THE GROUP CONSISTING OF OXYGEN ATOMS AND SULFUR ATOMS. 